Rivanol (RVN) binds to the double helical DNA with a high affinity, as
deduced from the absorption and fluorescence spectral data. Extensive
hypochromism and red shifts in the absorption spectra were observed w
hen RVN binds to calf thymus DNA (CT DNA), which suggested the interca
lation mechanism of RVN into DNA bases. Upon binding to DNA, the fluor
escence from RVN was efficiently quenched by the DNA bases, with no sh
ifts in the emission maximum. The large increases in the polarization
upon binding to CT DNA supported the intercalation of RVN into the hel
ix. Iodide quench in studies showed that the magnitude of K-sv of the
free RVN was higher than that of the bound RVN. The results of competi
tive binding studies showed that RVN can be displaced by ethidium brom
ide. Thermal denaturation experiments exhibited that the quenching of
the fluorescence from RVN by single strand (ssDNA) was smaller than th
at by double strand (dsDNA). The results of all above further studies
also proved the intercalation of RVN into DNA base stack. Quenching of
fluorescence from RVN by DNA can be employed for sensitive detection
of DNA. The limit of detection for CT DNA was 16 ng ml(-1). (C) 1997 E
lsevier Science B.V.